Mechanical-telephone exchange



(No Model.) 2 Sheets-Sheet 1. W. H. EASTMAN.

' MECHANICAL TELEPHONE EXCHANGE. N0. 375 316. Pateted De0.20,1887.

WIT EEEEEI. \/E TE] {Nd Model.) 2 Shets-Sheet 2.

- W. H. EASTMAN.

MBCHANICAL'TELEPHONE EXCHANGE- I No. 375,316. Patented Dec. 20, 1887.

WITIJESEEI-El. IPk/EPITDK I gag/Q UNITED STATES PATENT OFFICE.

. *ILLIAll/IH. EASTMAN, OF CONCORD, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE EUREKA TELEPHONE COMPANY, OF NA SHUA, NE HAMPSHIRE.

MECHANICAL-TELEPHONE EXCHANGE.

v SPECIFICATION forming part of Letters Patent No. 375,316, dated December 20, 1887.

Application filed May 9, 1887.

To aZZ whom, it may concern:

Be it known that 1, WILLIAM H. EASTMAN, a citizen of the United States, and a resident of Concord, in the county of Merrimac and State of New Hampshire, have invented a new and useful Improvement in Mechanical-Telephone Exchanges, of which the following is a specification.

The object of this invention is to enable any pair of a number of mechanical-telephone lines centering at an exchange to be connected in such a manner that the pair of lines are converted into one continuous line; and to this end it consists in the combination, substantially as and for the purpose hereinafter more fully set forth, of a series of mechanical-telephone lines centering at the office of the exchange on the arc of a semicircle, metallic loops or hooks on each of said lines near their points of attachment, a series-.- of connecting-wires, each having a hook at each end connected to ananglemurning and tension-equalizing device, as described, and a series of devices, as described, arranged one above the other,at the center of the semicircle for each connectingwire for tightening the same, whereby any pair of lines may be connected together, and the wire connecting said lines may be given the proper tension.

In the accompanying drawings, Figure l is a plan view of the exchange-table, showing the lines, the connecting-wire, the equalizingsupport, and the tightening device. Fig. 2 is a sectional view of the same. Fig. 3 is an enlargedplan view of the tension-equalizer and tightening device, and Fig. 4 is a sectional view of the tightening devices.

In theseveral figures the same letters represent the same parts.

Referring to the drawings, A is a stand or table, having upon it a series of posts, B B, arranged in the are of a semicircle, to each of .whioh one of the lines C, entering the office of the exchange, is attached. This table also supports the tightening devices, which are arranged one above each other at the center of the semicircle. From the posts the lines pass to a suitable semicircular frame, E, attached to the table, or suitably secured near the same in the room, and secured to the said frames by Serial No. 237,530. (No model.)

loops to a, and thence pass in the desired direction. By thus bringing all the lines to- .gcther and arranging the tightening devices at the center of the semicircle any pair of lines can be connected by a short wire,which,whe11 5 attached to the lines and suitably tightened, forms a curved connection between the two lines,and thus prevents the formation of sharp angles in the continuous line composed of the connected lines and connecting-wire, and the consequent interference with the proper transmission of molecular vibrations necessary for the transmission of speech.

Upon each of the lines C, near the post to which it is secured, is a metallic loop or hook, b, and T is a short connecting-wire, upon each end of which is a metallic hook, by means of which the short wire can be connected to the loops or hooks on the line-wire, and thus unite any pair of the same.

D is the angle-hanger and tensioirequalizer. Thisoonsists of a curved bar of metal, e, pivoted at its center tothe ends of the tightening device, and having pivoted to it at each end a 1ink,f, to which is pivoted a short curved bar 7 of metal, 9, and on each end of these shorter bars is a loop, h. The connecting-wire passes through these loops, and thus, when connected at each end to one of a pair of line-wires and tightened by the tightening device, it forms a 83 curve having an equal tension throughout. The device which Iprefer to use for tightening this wire consists of abar, H, of some suitable material,having a longitudinal slot in the same, and fitted upon a post fixed in the table and 8 5 passing through the slot. Arod, K, having a screw-thread on the same, passes through the outer end of the bar H and bears against the post, and consequently by turning this rod the distance of the tension-equalizer D from the 0 post I can be adjusted at will, so as to give any desired tension to the connecting-wire F. A series of these bars are arranged one above the other on the post I, and to each of them is attached a tension-regulator and connecting- 5 wire. Any other form of tightening device which will accomplish the same result may be used.

The lines are connected to a suitable electric annunciator and call-bell, such as is used in electric-telephone exchanges; but as this device is well known it is not shown.

The exchange is operated in the following manner. When any subscriberas, for example, one on line ii-desires to be put into connection with a subscriber on any other lineas, for example, on line 10he calls the central office by means of the electric call, and the annunciator indicates from which line the call has been received. The operator then attaches a small hand-telephone, L, to the loop or hook 1) upon the line from which the call has come, and learns from the subscriber with which line it is desired to connect. The operator then removes his hand-telephone and connects the two lines by any one of the short connecting-wires F by placing the hook at each end of said wire in the loops or hooks of the lines which are to be connected. He then operates the tightening device and tightens the connecting-wire until the proper tension is obtained, and thus converts thepair of lines into one continuous line, over which the desired conversation can be carried on. Should any other subscriber desire to have his line connected to another line, this can be effected by another one of the series of connectingwires.

It is obvious that the distance from each other on the semicircle of the lines which are to be connected will determine the extent to which the slotted bar or tightener will have to be moved to give the proper tension to the connecting-wire. By means of my device the proper tension is obtained, no matter how far apart the lines may be from one another on the semicircle.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

' 1. In a mechanical-telephone exchange, the combination, substantially as and for the purpose set forth, of the lines 0 O, centering at a common point, the semicircular frame E, the support A, the posts 13 B, arranged in a semicircular form on said support, and each having one of the lines attached thereto at a tension, the metallic loops or hooks b b on each of the lines, the wires F F, provided at each end with hooks or loops and arranged to connect any pair of line-wires as may be desired, a series of devices, said devices consisting of the curved bar E, links f f, curved bars g, and link h, for supporting each one of these wires F F, in the form of a curve and equalizing the tension of the same, the said devices being arranged one above the other on the medial line of the support A, and a series of adjusting devices for giving the connectingwires F F their proper tension, according to the pair of wires that may be connected, arranged one above the other at the center of the semicircle, and each connected, respect ively, to one of the tension-equalizing devices.

2. In a mechanical-telephone exchange, the combination, substantially as and for the purpose set i'orth, of the series of line-wires E, centering in a semicircle at a common point, the connecting-wires F F, devices for support ing these wires in a curve and equalizing the tension on the same, the post I, arranged near the center of the semicircle, the slotted bars H H on said post, attached to the tensionequalizing devices, and the screw K, each passing through a slotted bar and bearing against the post I.

In witness whereofI have hereunto set my hand in presence of the two subscribing witnesses.

\VILLIAM H. EASTMAN.

\Vitnesses:

J AS. W. Bnrees, ALEX. L. HAYES. 

